Pentafluorophenyl boron compounds such as, e.g., bis-, tris- and tetra-kispentafluorophenyl boron derivatives are useful in forming olefin polymerization catalyst complexes with metallocenes. Processes for the production of such compounds have been disclosed, for example, in U.S. Pat. Nos. 5,488,169, 5,493,056, 5,510,536 and 5,545,759 to Ikeda et al., and 5,473,036 to Piotrowski, the disclosures of which are incorporated herein by reference. However, the known processes for isolating, purifying and drying these pentafluorophenyl boron compounds from crude reaction mixtures require large amounts of solvent, multiple reactors, long cycle times, and low temperatures of operation. Often such processes involve the use of aqueous solutions which introduce water impurities to the final product. The product is typically dried in vacuum to water levels of about 2000 ppm. However, even very small amounts (e.g., 1000 ppm) of water can drastically diminish the activity of the catalyst complexes. In addition, so far as is known, previous methods of producing solid forms of such compounds have resulted in products having excessive average particle sizes, thus requiring grinding or other additional processing to obtain a more advantageous average particle size.
A need therefore exists for a facile process for the isolation, purification and drying of crude wet mixtures comprised of pentafluorophenyl boron compounds. Additionally, a need exists for an efficient process for producing solid pentafluorophenyl boron compounds with an average particle size of no more than about 200 microns.